Effects of aging on antagonist and agonist interactions with. beta. -adrenergic receptors on human leukocyte membranes

Conference · Sat Mar 01 00:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5385241

Zahniser, N R; Parker, D C; Bier-Laning, C M; Miller, J A; Gerber, J G; Nies, A S

Alterations in properties and/or coupling of ..beta..-adrenergic receptors might explain the diminished responsiveness to ..beta..-receptor agonists observed in aged humans. Polymorphonuclear (PMN) and mononuclear (MN) leukocytes were isolated on Percoll gradients from young or old healthy volunteers (25-34 and 60-76 yrs). Saturation isotherms of /sup 125/I-pindolol binding to PMN and MN membranes were generated. The affinities did not differ between the two age groups or cell types (52-61 pM). The number of receptors differed only on MN membranes (PMN young: 37 +/- 5.7, old: 44 +/- 6.7; MN young: 55 +/- 7.1, old: 122 +/- 23 fmol/mg protein; N = 6-8); however, this apparent increase became a decrease if the data were expressed in fmol/million cells (MN young: 0.82 +/- 0.12; old: 0.57 +/- 0.10) suggesting alterations in protein content or cell types rather than receptors in aged MN's. Agonist affinities, determined from isoproterenol competition curves in the absence and presence of GTP, were not different between the two age groups or cell types. In agreement with most previous reports, no change with aging in the properties of antagonist binding to ..beta..-adrenergic receptors on MN's was detected. However, in contrast with an earlier report, no changes in agonist binding or coupling of the receptor in MN's from the elderly were found. These observations were extended to PMN's and suggest that changes in ..beta..-adrenergic receptors may not underlie age-related decreases in isoproterenol responsiveness.

• Research Organization: Univ. of Colorado Health Science Center, Denver
• OSTI ID: 5385241
• Report Number(s): CONF-8604222-; TRN: 86-026607
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:3; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
AGING
BIOLOGICAL EFFECTS
RECEPTORS
BIOCHEMICAL REACTION KINETICS
SYMPATHOMIMETICS
AFFINITY
AGED ADULTS
CELL MEMBRANES
IODINE 125
LEUKOCYTES
TRACER TECHNIQUES
VASODILATORS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CARDIOVASCULAR AGENTS
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MATERIALS
MEMBRANE PROTEINS
MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
REACTION KINETICS
550201* - Biochemistry- Tracer Techniques